User manual
7. Principles and application of electrosurgical apparatus
Theoreticalintroduction
Electrosurgery means application of radiofrequency (RF/VF) current within the scope
of approx. 300 kHz to 5 MHz in order to achieve the required result of a surgical intervention.
Typically, this concerns coagulation (conversion of a colloid system into a gross dispersive
system) or surgical sections, when the tissue is affected or impaired. Further on, it might be
desiccation of the tissue or destruction of the tissue. Physical operation principle is given by
the effect of distributed heat within the tissue from the RF/VF stream via a mechanism of
resistance or joule heat. This method allows for cutting and coagulating the tissue at the same
time, and that is the main advantage used in electrosurgery ever since it was discovered,
which was approx. in 1920. Although the first attempts regarding the utilization of heat for
therapeutic purposes were realized several thousand years before Christ, it was not until 1920
that such technology was available and the electrotechnical industry became so developed that
it was possible to manufacture such apparatus. Typical effects of electrosurgical procedures
may be described as follows. It is the so called “white coagulation”, named after its external
manifestation on the tissue, when the proteins in the tissue degrade, typically at 50-90 °C.
Then it is the so called “black coagulation”, or else the “carbonization” (carbonification),
when the tissue is completely desiccated and reduced to carbonized residue at higher
temperatures. And there is the third effect in the form of the cutting, when the tissue structures
are divided by fast evaporation of little volumes of water in the tissue. These three effects or
manifestations appear in certain combinations, when they depend on the current used and on
the voltage of the active (surgical) electrode, which is energized by the high-frequency
electrosurgical generator.
Electrosurgery is a suitable addition to the current surgical procedures, more than any
other device or method. At the same time, it significantly reduces sickness rate and morbidity
caused by surgical interventions. This is namely given by the fact that minimized time is
required under anaesthesia, and also by the fact that bleeding during surgeries and afterwards
is minimized. Today, for example, we cannot imagine demanding neurosurgical operations
without the electrosurgery methods. Just as well, surgeries on an open heart and many urology
operations could not be carried out at all without electrosurgery.
You will find animations demonstrating the electrosurgery principles on the subject’s website.
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